An extremist activist who had close links with one of the Woolwich killers and a range of other convicted terrorists should be the subject of a rigorous police inquiry, the Government’s former reviewer of anti-terrorism legislation said last night.

Lord Carlile of Berriew, QC, led calls for an investigation into Anjem Choudary’s connections with Michael Adebolajo who attended meetings and demonstrations organised by the banned al-Muhajiroun organisation and its offshoots.

Keith Vaz, leader of the Commons Home Affairs Committee, backed the call as an analysis of terrorism cases since 1998 claimed that almost one in five of those convicted had